1. Field of the Invention
The present invention relates to color monitors and displays, and more particularly the present invention relates to calibrating and standardizing the output of a color display device.
2. Description of the Related Art
The currently accepted method of characterizing the input-output of an analog RGB color CRT monitor is to assume that the input voltage to the monitor is related to the output brightness of the monitor by a “gamma” function. The gamma function is utilized to define the relationship between the input voltage and the output brightness of the monitor. The brightness of the monitor should be equal to a constant multiplied by the input voltage raised to the power of gamma. Gamma is a rational number between zero and infinity which is provided by a monitor's manufacturer and is based on measurements made by the manufacturer. Via experimental observation, it has been determined that the gamma function, though the standard in the industry, is inaccurate. The gamma function can provide an error that can exceed 4 foot-lamberts over the full brightness range of the monitor; the gamma number is generally an estimation by the CRT's manufacturer based on empirical measurements on a specific monitor and then averaged or generalized for all similar monitors.
Furthermore, color monitors generally generate a color picture via a brightness mixture of red, green and blue. Since red, green and blue are generated by separate circuits, the gamma function for each should be different. To date, only a single gamma is used for all three colors.
The importance of accurate color is becoming of paramount importance in the computer monitor industry. The need for and importance of accurate color has come about, to some degree, due to the increased amount of commerce taking place on the World Wide Web or Internet. For example, an Internet site might sell clothing. The site owner would like the correct color of the clothing to be displayed on the viewer's monitor so that the viewer will have better confidence when buying the product. At present, the gamma function will not necessarily allow the potential buyer to view the correct color of the clothing. This is a significant problem in the area of standardizing the color in a color display device.
Thus, there is a need for a method of providing a color monitor or color display device the ability to correctly and accurately display the color(s) that should be displayed. Furthermore, there is a need for providing a color monitor that utilizes more than the single gamma number in order to predict and provide a brightness output that is characterized by a standardized signal input-brightness output characteristic. Furthermore, what is needed is a method and apparatus for characterizing each color channel of a color monitor separately in order to enhance color fidelity of a color display device. Also, there is a need for a color display device that stores its own input-to-output brightness characteristics.